In older adults, small-fiber peripheral neuropathy is most often caused by vitamin deficiency, cancer, diabetes, or chemotherapy. It involves the loss of the small, mostly unmediated sensory and autonomic nerve axons in the peripheral nervous system. An objective diagnosis is made by skin biopsy showing loss of nociceptive epidermal nerve fibers and by tests of autonomic function. However, this kind of diagnosis is not usually recommended in patients whose chronic widespread pain began in childhood or adolescence. In 2007, Dr. Oaklander described a healthy 20 year old man who developed burning pain with redness and swelling of his hands and feet. She diagnosed him with SFPN. After that she said that she started to notice more and more cases in younger patients, leading to a new study.
In the new study, Dr. Oaklander and Dr. Max Klein analyzed all the clinical data from 41 patients, who were under 21 when their pain began. Based on results from skin and nerve biopsies and physiological measures of autonomic function, more than half of the patients met diagnostic criteria for SFPN. Some patterns did emerge from the medical histories. A third of the patients had a history of autoimmune disease, and may displayed immune-related abnormalities on blood tests. In some of the children, tests detected autoantibodies to voltage-gated potassium channels (VGKC) or N-type calcium channels, molecules that have recently been implicated in chronic pain